1. Field of the Invention
The present invention relates in general to an engine, and in particular to a component layout for a marine engine, including an arrangement of the fuel pump.
2. Description of Related Art
Internal combustion engines are commonly used to power small watercrafts such as personal watercraft. These watercraft include a hull which defines an engine compartment Personal watercraft often employ an inline, multi-cylinder, crankcase compression, two-cycle engine. The engine conventionally lies within the engine compartment with the in-line cylinders aligned along a longitudinal axis of the watercraft hull. The output shaft of the engine is coupled to a water propulsion device of the watercraft, such as a jet propulsion unit.
Generally, the engine of the small watercraft also includes an air intake system, an exhaust system, a fuel supply system, and other components to operate the engine. Air is supplied to the engine from the outside of the hull for use in the combustion process. Typically, air flows through one or more ducts in the hull into the engine compartment, and then through the intake system to the cylinders. An exhaust system communicates with the cylinders of the engine and extends to a discharge that is located near the stern of the watercraft.
Fuel is also supplied to the engine for use in the combustion process. In order to accurately meter the fuel and improve engine operating efficiency and performance, the fuel may be injected with one or more fuel injectors. Each injector has an electrically operated valve which selectively opens and closes, controlling the flow of fuel through the injectors to the engine. In this arrangement, fuel is supplied to the fuel injectors at a high pressure by a fuel pump.
Personal watercraft also commonly include an access opening that is formed in the watercraft deck above the engine. A longitudinally extending, straddle-type seat normally covers the access opening to close the engine compartment. On occasions, a rider may need to open the access opening while the watercraft is floating in a body of water in order to make minor repairs or adjustments.
Prior arrangements of the fuel pump within the engine compartment posed the risk that water could enter the engine compartment through the uncovered access opening and contact the fuel pump, which consequently could damage the fuel pump and/or its electrical contacts. In addition, water that enters the engine compartment also tends to splash about within the engine compartment due to the pitching and rocking movement of the watercraft as it moves through the water With either direct contact or subsequent internal splashing, the water can corrode or otherwise damage the pump and/or interrupt the electrical current flow to the pump. In some cases, this may permanently damage the pump as well as affect the operation of the engine.